Self powered remote trip indicator
US5508875A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 6, 1993 |
| Grant date | Apr 16, 1996 |
| Priority date | — |
| Expiry date | Oct 6, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02H1/06
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A self powered trip indicator remotely reads out parameters such as the type of trip detected in a contactor or motor starter circuit controllably coupling a power line to a load. The contactor circuit imposes signalling pulses on a trip status signal following a transition of the signal to a fault-indicating level, the pulses representing the parameters. The remote trip indicator derives operative power from the trip signal, and decodes the parameter from the pulses, using a decoder such as a counter to accumulate a binary multiple count of pulses, the result being indicated on LEDs coupled to outputs of the decoder. A switching circuit generates a short reset pulse to the counter at a leading transition following a pulse or level of a width exceeding a time limited by an RC combination coupled to the counter reset input. An RC timing circuit on the input side distinguishes the leading transition from other transitions by disabling a subsequent reset for a minimum time after generation of a first reset, during which time the pulses are counted and the result remains stable on the indicator LEDs. The circuit permits a reset after a longer duration between transitions, after which t…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.